Distinguishing Between Infections, Contamination, and Colonization

While Corynebacterium species are often seen as contaminants in clinical specimens, there are instances where the organism is implicated as the cause of an infection, and treatment is initiated. In the initial specimen Gram stain, where gram-positive bacilli are surrounded by inflammatory cells such as polymorphonuclear cells (PMNs), and the organism is isolated on repeated cultures from the same site, could indicate that the Corynebacterium recovered may be the pathogen causing the infection.

Any gram-positive bacilli recovered from a clinical specimen may initially be considered a contaminant, however, the recovery of these organisms should be correlated carefully with the clinical history of the patient and the potential significance of the isolate.

Multiple corynebacterial microorganisms may attach to indwelling devices. Once the colonized device is removed or replaced, the symptoms of infection often dissipate, and no further treatment is needed.